1. Field of the Invention
This invention relates, generally, to labeling machines. More particularly, it relates to a labeling machine that employs mechanical structure to achieve synchronization of parts.
2. Description of Prior Art
Labeling machines sequentially transfer labels from a backing onto product packages. Typically, the backing is a continuous strip of paper or paper substitute having a label-carrying side that has been treated with a very light adhesive. The labels are arrayed upon the adhesive carrying side of the backing in longitudinally spaced apart alignment with one another, The adhesive has sufficient strength to hold the labels onto the backing only if little or no separation force is applied. The backing having labels follows a path of travel begins at a supply drum or reel, continues to a label-peeling means positioned at a label-applying station where labels are sequentially separated from the backing and individually applied to product packages carried by a conveyor belt or other conveyor means, and ends at a take-up drum or reel that collects the label-free backing.
In prior machines, a photoelectric eye or similar device that distinguishes between the labels and the backing to which they are adhered is positioned between the supply drum and the label peeling device. When a space between labels is detected, the photoelectric eye sends a stop signal to a braking means that stops rotation of the supply and take-up drums. However, the package conveyor belt continues to move, thererby allowing a just labeled product package to enter the label-applying station. The photoelectric eye then sends a start signal so the supply drum and take-up drum resume rotation so that another label can be applied. When another gap between labels on the backing is detected, the cycle repeats itself. In this way, there is no need to start and stop the conveyor as in still earlier machines.
However, photoelectric eyes are not inexpensive, nor are they completely reliable. Various anomalies in the backing, for example, for example can cause such a device to miss detection of a gap between labels. This causes the backing to continue traveling at a time it should held motionless, leading to misapplied labels.
What is needed, then, is a labeling machine that enables continuous operation of a transport but which is not reliant upon the technology of photoelectric eyes.
However it was not obvious to those of ordinary skill in this art how an improved labeling machine could be provided, in view of the art considered as a whole at the time the present invention was made.
The long-standing but heretofore unfulfilled need for an innovation that overcomes limitations of the prior art is now met by a new, useful and nonobvious invention. The present novel labeling machine includes a rotatable-mounted supply drum, an elongate length of label-carrying backing coiled about the supply drum, and a rotatably-mounted take-up drum for collecting the backing after labels have been removed therefrom. A label peeling means, positioned between the supply drum and the take-up drum, sequentially removes labels from the backing and applies them to product packages that are transported to a label applying station by a conveyor means.
A rotatably mounted drive wheel has a plurality of circumferentially spaced apart knurled sections formed on its circumference and a plurality of circumferentially spaced apart recessed sections formed on its circumference. The knurled sections and recessed sections are disposed in alternating sequence about the circumference of the drive wheel. A suitable drive means including a drive shaft is provided for continuously rotating the drive wheel at a predetermined number of revolutions per minute. A rotatably mounted pressure wheel is disposed in meshing engagement with the drive wheel. A detent means opposes travel of the backing, but it momentarily releases the backing just before a knurled section of the drive wheel is engaged by the pressure wheel so that the rotation of the drive wheel drives the backing through the label peeling means and effects application of a label to a product package at the label applying station. The detent is not released when the backing is disposed between a drive wheel recessed section and the pressure wheel; the detent means holds the backing against travel during that segment of the rotation of the drive wheel so that a product package carried by said conveyor means travels a predetermined distance and no label is applied thereto.
Each of the knurled sections has a length substantially equal to the sum of the common length of the labels being applied plus the space between the labels in a particular job so that the rotation of the drive wheel at the predetermined number of revolutions per minute sequentially brings the knurled sections into juxtaposition with the pressure wheel for a predetermined time. The predetermined amount of time is substantially equal to the time required for application of a label to a product package.
The drive wheel is collectively formed by three disc drives, each of which is mounted on the common drive shaft for conjoint rotation therewith. Two of the three discs are in rotational alignment with one another so that their respective knurled sections engages the pressure wheel at the same time and so that their respective recessed sections are in non engaging relation to the pressure wheel at the same time. A third disc is rotationally displaced relative to the other discs so that its knurled section engages the pressure wheel before engagement thereof by the respective knurled section of the other discs. The third disc may be mounted at any rotational position of adjustment on the drive shaft. If its knurled section is slightly rotationally advanced relative to the rotation of the other discs, the novel labeling machine is capable of applying slightly longer labels to a product. If the knurled section is even more advanced, the machine can handle labels of even greater length. In other words, the amount of rotational advance of the third disc is adjusted so that the effective combined circumferential extent of the respective knurled sections of all three discs matches the sum of the length of the distance between the label to be applied, plus the length of a major portion of the label.
Each of the recessed sections has a predetermined extent so that the rotation of the drive wheel at the predetermined number of revolutions per minute brings the recessed sections into juxtaposition with the pressure wheel for a predetermined amount of time The predetermined amount of time is substantially equal to the time required for a product package that has just been labeled to exit the label-applying station and for a following product package to enter the label applying station.
The primary object of this invention is to provide a labeling machine formed exclusively of mechanical parts so that it is more reliable than machines that rely on photoelectric eyes.
Another important object is to provide a labeling machine having moving parts that are synchronized with one another by mechanical means so that mislabeling is minimized or eliminated.
Another major object is to provide a labeling machine having mechanical parts that are easily adjustable to enable the machine to apply labels of different lengths.
These and other important objects, features and advantages of the invention will become apparent as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements and arrangements of parts that will be exemplified in the construction hereinafter set forth and the scope of the invention will be indicated in the claims.